With the recent development of bicycle chainrings, the sizes of the chainrings have a lot more variety than before. One example is the Suntour.TM. Micro Drive.TM. chainring which has 20 teeth on the smallest chainring and 42 teeth on the largest chainring. With existing anti-chain wrap devices, there is difficulty mounting the device at the proper position to function efficiently. The invention provides for front-to-rear and side-to-side adjustability of the anti-chain wrap device in order to accommodate the wide variety of chainring sizes in use.
Another change on the chainring design is the addition of extra teeth on the frame side of the middle chainring for more efficient shifting to the middle chainring from the small chainring and because of the extra teeth, unequal spacing between the small and middle and middle and large chainrings. One example is the Shimano XTR chainring. When the Shimano XTR chainring is mounted with existing anti-chain wrap devices, the extra teeth will cause interference resulting in improper function of the device. The invention provides for clearance for the extra teeth and adjustability to fit different chainring spacings.
It is desirable to provide more clearance for the new wider tires, while attempting to keep the chainrings close into the center plane of the frame. While also trying to make the distance between the bicycle bottom bracket and the rear drive axle shorter. The existing anti-chain wrap devices become an additional clearance problem in this regard. The invention is more compact and allows for better clearances.
In order to accommodate the above two examples and other changes on the chainrings, the anti-wrap chain device is created so that it will have more adjustability and will not cause interference with the chainring when mounted at the correct position.
The invention also incorporates a fixed position rear derailleur cable guide and can incorporate a fixed position fender mount as well.
The object of the invention is to provide an improved anti-chain wrap device which has a narrower configuration for improved tire/chainring clearance, and can accommodate different sizes, spacings and unusual teeth configurations of chainrings, and provide consistent cable guide and fender mount locations.